Based on the development of metal organic chemical vapor deposition method, molecular beam epitaxy method, and the like of gallium nitride (GaN), red, green and blue light emitting diodes (LEDs) that may have high luminance and realize white light have been developed.
Such LEDs do not contain environmentally harmful materials such as mercury (Hg), which is used in existing luminaires, such as incandescent lamps and fluorescent lamps and thus exhibit excellent eco-friendliness, long lifespan, and low power-consumption and thus are replacing conventional light sources. A core competitive factor in such LEDs is to achieve high luminance using chips with high efficiency and high power output and packaging techniques.
To realize high luminance, it is important to increase light extraction efficiency. To increase light extraction efficiency, research into various methods using flip-chip structures, surface texturing, patterned sapphire substrates (PSSs), a photonic crystal technology, anti-reflection layer structures, and the like is underway.
FIG. 1 is a plan view of a conventional light emitting device 10.
The light emitting device 10 illustrated in FIG. 1 consists of first and second electrode pads 22 and 24, nine light emitting cells 40, and connection wires 30 electrically connecting the adjacent light emitting cells 40. In this regard, the neighboring light emitting cells 40 are connected to each other by the connection wire 30. When the connection wire 30 is broken, there is a problem that the light emitting element 10 is not operated.